Christie’s has come under attack for refusing to disclose the location of an Italian 18th-century painting, stolen from a Jewish family in Vienna by the Gestapo.

The descendants of the Nazi victims failed in US courts to get the firm to reveal the painting’s location after a former employee of the auction house said that it is in the home of one of the company’s clients. Christie’s has also been attacked for failing to publicise the Nazi provenance of a 17th-century Dutch painting consigned to them by the German collector, Carl Shünemann, and subsequently returned to him. The painting, by Jacob Duck, was discovered by Christie’s researchers to have been stolen by the Nazis in 1937 from a Jewish couple who later died in Auschwitz. In a statement about the Duck painting, Catherine Fenston of Christie’s said “we do not have the legal right to breach the duty of confidentiality [with our vendors] by contacting third parties without the vendor’s permission...The way we deal with [Nazi loot claims] is governed by the rules of law.”